Stock distributor



June 2, 1964 FAIR 3,135,654

STOCK DISTRIBUTOR Filed July 11, 1962 4 Sheets-Sheet 1 III I, 1",..."IIIIIIIIIIIIIIIIIIII,

INVENTOR. ALBERT E. HAROLD FAIR ATTORNEY.

June 2, 1964 A FA|R STOCK DISTRIBUTOR Filed July 11, 1962 4 Sheets-Sheet2 j z It n E A q- 9'. N

I N N /8 N z z m INVENTOR. ALBERT E HAROLD FAIR q m ATTORNEY.

June 2, 1964 A. E. H. FAIR 3,135,654

STOCK DISTRIBUTOR Filed July 11, 1962 4 Sheets-Sheet 5 ALBERT E. HAROLDFAIR BY @wm@ ATTORNEY.

June 2, 1964 FAIR 3,135,654

STOCK DISTRIBUTOR Filed July 11, 1962 4 Sheets-Sheet 4 INVENTOR. ALBERTE. HAROLD FAIR ATTORNEY United States Patent 3,135,654 fiTOCKDISTRIEEUTOR Albert E. Harold Fair, 27 Neweli Road, Erookline, Mass.Filed July 11, 1962, Ser. No. 209,136 in claims. (or. 162-336) Thisinvention relates broadly, to the control of a confined stream of anaqueous suspension of papermaking fibers (i.e. a stream of liquid havingfibers suspended or dispersed therein), and more particularlycomprehends new and useful improvernnts and structural refinements inflow control means for the spreading and quieting of such streams in thestock conduit system of the web-forming machinery.

The control of such a confined stock stream is of great importance inthe operation of papermaking machines of various types where it isnecessary to deliver the fibercontaining liquid stock from which thepaper is manufactured to the Web-forming region of the machine in theform of a wide and relatively shallow flowing stream of rectangularcross-section which may be under considerable pressure.

The method of delivering the stream of papermaking stock to the flowcontrol means envisions the use of a suitable pump, in conjunction witha closed conduit system wherein the confined stock stream is usuallycircular in outline, so as to necessitate the transformation thereofinto a shallow, relatively wide stream which is required at theweb-forming region of the papermaking machine.

It is known that to produce a paper sheet having uniform physicalproperties, the paper stock (which may include water, pulp, fiber,filler, dye, glue, etc.) delivered to the web-forming region should beevenly distributed across the machine width. Expressed mathematically,this means that the kinetic energy and potential energy in unit areas ofthe stream delivered to the web-forming region should be as uniform aspossible throughout the stream cross-section, and in addition, theentire stream should be maintained in a condition which is as near tosteady-state flow as it is posisble to obtain. In other words, the stockshould be delivered to the web-forming region at a uniform pressure andvelocity across the width of the machine, and the pressure and velocityrelationship should be invariant with time.

This invention envisions a new and novel stock distributor or flowspreader as a component of the closed conduit system and as a cooperantinstrumentality with a new and novel head box and its inclusiveinterference devices as another component of the closed conduit system,which flow spreader and head box participate in a conjoint result ofsupplying a single, steady, wide, smooth, thoroughly mixed, uniformstream of the aqueous suspension, free from large eddies, orfiocculations, to the web forming components of the machine.

The objects of the invention are accomplished by the provision ofcooperating flow-spreading and quieting means in a conduit system makingmore positive and more effective the control of a flowing stream ofpapermaking stock.

It would be indicated, ab initio, that while a machine of theFourdrinier type is herein disclosed as coacting with the structure ofthe invention, it is envisioned that cylinder and/or other types ofpapermaking machines may be employed with equal ease and facility.

It will be helpful to an understanding of the invention first toconsider briefly some of the more essential and important features andaspects of the prior art and of the present invention, so that same maybe kept in mind during subsequent reading of the detailed description ofthe practical embodiments of many of my improvements and representativeillustrations thereof in the hereunto annexed drawings.

As known, the head box or fiow box delivers to the wire a suspension offiber and other additives dispersed in a water vehicle, said deliverybeing at a predetermined velocity through an orifice, commonly called aslice, which extends laterally across the width of the machine, fordeposit upon a web-forming means. Such web-forming means, in the case ofa Fourdrinier type of machine, comprises a continuously-travellingendless wire, having a generally horizontally-extending run throughwhich, by means including capillary action and surface tension, theWater is drawn so as to leave upon the upper planar surface of the wirea mat or Web of the papermaking fibers.

The desideratum of supplying to each increment of the web-forming areaan equal and uniform distribution of fibers, under steady-state flowconditions, in the form of a moving mass of Water and fiber insuspension, with each lamina thereof moving in the machine direction atthe same velocity and under such pressure as allows a delivery velocityequal to the speed of the travelling forming wire, is well understoodand accepted in the papermaking art, and various flow controlarrangements have been suggested and used in an effort to attain theseconditions, but such have not been altogether satisfactory.

The factors for attaining the desiratum, heretofore, have beeninherently conflicting and notoriously incapable of correlation exceptat low operating speeds, Wherefore most machine operations have beenconducted under compromise conditions.

As if the difficulties in formation were not sufficient in and bythemselves, they have been accentuated and aggravated by increases inmachine widths and speeds as the papermaking machinery art has developedin its forward progress. As the widths are increased and/or as thespeeds are increased, all of the elements and inherent problems areaggravated many times the proportion of such increases. 7 As machinespeeds have increased, the use of relatively high flow velocities hasbeen necessitated and the head box has become one of the limitingfactors of the machine. To obtain theoretical heads at speeds of 2000feet/minute and over, the head box has had to be of such height as to beungainly. To effectively eliminate or cut down the size of the head box,various pressure devices with fiow spreaders or flow eveners have beendesigned to distribute the stock uniformly across the full machine widthat proper velocities and without cross currents and in uniformdispersion.

Disturbingly, a high flow velocity is usually associated with violentcurrents in the flow direction. In some cases, the desireddefiocculation is achieved, but at the expense of creatingirregularities across the web, due to uneven streams within the greatermass of fiber suspension. Such lack of uinformity deleteriously alfectsthe web strength and causes unevenness which interferes with thequaltity of the end product.

It is well known that pulp fibers will flocculate or settle unlessagitated or kept in motion or caused by some physical-chemical means tooppose each other, which flocculation will cause a mottled or blotchyformation and which settling will cause a massing of fibers, with themasses breaking away and causing spots in the sheet, and if largeenough, breaks at the presses and/or at other points.

This condition presents consistent difficulties to the task ofdelivering a uniform suspension of fibers to the webforming region, andis aggravated by the problems inherent in avoiding the formation ofcurrents in the suspension.

As to directionality, an absence of parallel flow in the machinedirection signifies a presence of cross currents which will causevariations in the quantity of fibers delivered across the lateral widthof the forming area, resulting in heavy and light streaks across theformed sheet.

It follows, therefore, that optimum formation depends upon two factors:(1) a uniform flow of the mixture of pulp and water to the web-formingarea; and (2) a uniform dispersion of the fibers within the carryingmedium.

I am aware of a paucity of suitable instrumentation which has been thestimulus for improvisations in prior art papermaking machines,especially for purposes or" effectuating high speed operation. Untilnow, no satisfactory flow control system has been forthcoming which soadmirably combines, in a simple manner, the multiplicity of desirablefeatures for both low speed and high speed operation.

Relatively complicated countercurrent flow devices have been known. Oneapproach has visualized resort to multiple feeds to the head box bymeans of small pipes across the machine width, the stock being normallypumped thereto through a single pipe to a manifold having a plurality ofoutlets leading into the head box, each outlet serving, objectionably,to create its own set of currents or turbulences. Such a plurality offorward currents had led to unequal velocities between the points offlow, not to mention diflicult-to-iron-out dead spots, eddies andfluctuating cross currents.

Numerous supplemental correctional devices have been resorted to, suchas perforated boards, adjustable partitions, racks, discs, and the like,to eliminate the created conditions, but notwithstanding variousattempts to merge these currents, it has been exceedingly difficult todestroy them altogether, wherefore they persist at the slice.

Also employed have been head boxes with relatively large compartments,resulting in slow flows of stock streams so that the pulp fiberssuspended in the carrier become quiet and flocculation and settlingoccur, leading to a mottled and uneven sheet. It is obviously requisite,therefore, to keep the mass moving at a velocity suflicient to precludesuch state of quiet and the resultant flocculation and settling. Effortsin this direction involving the use of a plurality of adjustablepartitions have encouraged the forming of longitudinal currents in thehead box flow and have allowed an excess of exposed surfaces.

Other systems have incorporated explosion chambers and flow manifoldsand turbulence, caused by a sudden flow enlargement or by a quickreversal of flow direction, tends to break up flocculation and toprovide additional mixing. Concomitantly, however, it usually allowseddies, spirals and cross currents and induces air entrapment to furtherdisturb formation.

The prior constructions, aimed in various ways to solve the inherentproblems, appear consistently to be attended with certain seriousdisadvantages and limitations which have militated against their moregeneral adoption. In contradistinction, I have discovered that all ofthese difficulties and disadvantages are overcome and new advantagesaccrue in the system of the present invention.

I accomplish this by the provision of a structure which comprehendsimprovements in the stock-receiving component, inclusive of the flowdistributor, which converts a flowing stock stream of a certaincross-section to a flowing, yet constantly agitated, stock stream ofanother crosssection and allows the attainment of a Well and uniformlydispersed mixture having little, if any, forward currents to causeunevenness in the formed web, and further inclusive of the head box,which allows a forward velocity of the suspension, at the point of entryto the pond, which is relatively slower and in better conformation thanthat allowed in other known types of head boxes and which includesinternal agitation means involving the inducement of small organizedcross currents to keep the fibers dispersed, and, therefore, amenable toclose and uniform web formation, and to equalize the strength of theformed web in both forward and cross directions.

The flow control means of the invention, as aforesaid, has particularrelation to the control of a flowing stream of stock, comprising adispersion or suspension of fibers, Within a conduit system useful fortransforming the flowing stock stream as it is discharged to the inflowend of a flow spreader from an inflow conduit of one cross section intoa relatively shallow, elongated reetangularlyshaped form as it isdelivered from its outflow end with an exact hydraulic balance beingattained at all points along the width so as to allow an equal quantityof stock to each unit width of the head box and, in turn, of the sliceand of the web-forming elements of the machine.

The flow spreader, as used in the conduit system hereof, comprisesessentially a rigid-walled, laterally-diverging conduit adapted to beconnected into the system between the fan pump and the web-formingregion of the equipment for the purpose of effecting a widening andreduction in depth of the flowing stream. Thereby, a gradual flatteningof the round cross-section of the stock stream and a gradual pinching ofits central flat area, so as to preclude a concentration of flow at itscenter, is allowed with a minimization of surface contact, it being wellaccepted with the greater the surface area which the flowing streamcontacts, the greater the hazard.

The flow spreader is generally of fan shape and functions, within arelatively short distance, to transform the flow from the roundcross-section to a relatively flat pattern by virtue of the gradualflattening. A mere flattening of the cross-section and no more, wouldcreate a more or less slot-shaped outflow adjacent the inflow of thehead box resulting in an obviously heavier flow of stock at the centerof the outflow than at its edges, the distance through the center beingshorter and the friction thereat being less. Contrariwise however, thechamber of my flow spreader is depressed in the area of its midsection,restricting the flow thereat and forcing the flowing stream to bedistributed more evenly across the entirety of the width of the inlet tothe head box.

The conduit section between the fan pump and the throat or inflow end ofthe flow spreader will be suitably dimensioned and shaped so as toestablish the flowing stream in a substantially steady-state flowcondition as it enters the flow spreader.

Additionally, the conduit section between the outflow end of the flowspreader and the head box will be likewise suitably dimensioned andshaped so as to maintain the flow outwardly of the flow spreader in asteadystate condition until it enters the web-forming region.

The configuration of the flow spreader per se is such that the stockstream flowing therethrough is maintained in a substantiallysteady-state flow condition, such that as it is delivered to its outflowend, it will possess a more uniform pressure across the entirety of itswidth and a more uniform velocity throughout its cross-sectional areathan it would have were the control devices not present.

Cooperatively related to my flow distributor is a head box of a designwhich advantageously is dimensioned and shaped so as to maintain theflow outwardly of the flow spreader in a steady-state condition until itenters the web forming region, while with the aid of interferencedevices, simultaneously creating small intermittent and organized crosscurrents so as to destroy the normally-present fluctuating longitudinalcurrents.

The attainment of more thorough fiber dispersion allows the increasingof the percentage of fibers in suspension, thereby allowing a reductionin the percentage of carrier used, which in turn reduces the amount ofcarrier subsequently to be removed, all permitting higher operatingspeeds, greater production rates, and substantial savings in power usedfor pumping the suspension to the web forming components.

Within the head box, a slowing of the flow ensues by the use of agradually enlarging first pass as the flow approaches an adjustable dam,which means aid in mainraining an even flow of fiber suspension at areduced velocity wherefor uneven currents are precluded and a relativelyplacid pond results.

Due to the fact that such slowing will allow flocculation, it isnecessary to provide agitation to deflocculate the suspension andsimultaneously to prevent the formation of substantial currents in themixture of water and solids and same is accomplished herein by agitatormeans which are designed to turn at variable speeds to suit the gradesof paper and machine speeds being run.

Conceivably, installation of the structure hereof may be made in a headbox of the closed inlet or pressure type, its advantage in such instancebeing readily appreciated when it is recognized that the properfunctioning of such types of head boxes is absolutely dependent upon aproper flow to the nozzle. With a closed inlet or pressure type headbox, it is diflicult to correct unevenness of flow other than byadjustment of the slice lip, which adjustment may cause streaks in theflow on the wire. The system hereof superbly overcomes this difliculty.

When applied to a cylinder machine vat, the structure hereof may beplaced under the vat and the discharge end connected to the vat by asuitable connecting fitting of full vat width, the discharge velocityfrom the flow spreader being reduced either in the connecting fitting orin approach passages in the vat and before release into the open endpond at the forming point so as to prevent turbulence. The agitationmeans of the structure may be applied in the chamber immediately beforethe inlet to the vat.

Before proceeding further, a consideration of the phenomenon ofseparation is indicated. Such frequently occurs within a stream of stockflowing through a closed conduit when it loses energy because offrictional contact with the conduit walls, which loss is evidenced by areduction in the velocity of the stock stream adjacent said conduitWalls. The velocity of the fluid is zero, or near zero, at the walls ofthe conduit and increases rapidly in a direction inwardly from the wallsuntil it attains free stream velocity (i.e. the velocity of the stockstream whose energy is unaffected by the presence of the conduit walls).In a narrow region adjacent the wall, the fluid moves at a velocitywhich is slower than its free stream velocity and such is generallyreferred to as the boundary of the stock stream. Where the stock streamsuddenly moves into an area of higher pressure (when it moves into asection of greatly increasing cross-sectional area) the fluid in theboundary layer of the moving stock stream may not possess suflicientenergy to overcome the higher pressure which it encounters, and in suchinstance, the dead or low energy fluid is forced to stop and may evenactually flow in a reverse direction, thus separating from the mainfluid stream and initiating vortex formation at the separation point.

I have determined that this separation may be prevented by graduallypinching the central portion of the ever-widening cross-sectional areaof the stock stream so as to divert increasing portions of the flowtoward the side walls of the flow spreader so as to accomplish theremoval of the low energy fluid from the boundary layer of the stream atany point where the boundary layer is about to separate from the mainstream.

Removal of the low energy fluid from the boundary layer of the streammay allow a new boundary layer to start to form downstream thereof.Instarting to form, such boundary layer will possess enough energy tomove downstream for some distance before it loses sufi'icient energy byfrictional contact with the side walls to separate from the main streamand by such time, still further increasing quantities or portions of theflow have been diverted toward the side walls wherefor separation of thenewly-forming boundary layer, as it is about to separate from the mainstream, is precluded.

By suitably dimensioning the pinching of the walls of the flow spreader,one is able to completely eliminate the 6 phenomenon of separation andthe resulting eddy formation in the fluid stream.

The physical embodiments here described will be indicative of but two ofthe multiplicity of ways in and purposes for which the principle of theinvention may be employed. It will be apparent, however, that thespecific physical embodiments delineated, albeit the preferred eX-emplifications, are only indicative of but two of the multiplicity ofways in and purposes for which the principles of the invention may beemployed, said embodiments not being intended to be exhaustive of, norlimiting of, the spirit or scope hereof. On the contrary, they aremerely exemplary and explanatory for the purpose of illustrating theinvention that others skilled in the art to which the inventionpertains, may so fully understand the invention, its principles, and theapplications thereof, that they may embody and adapt them in numerousforms, each as may be best suited to the conditions and requirements ofany particular use.

The invention will be better understood from a consideration of thedetailed description which follows, when read in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a broken side elevational view of a stock distributor or flowspreader and flow box, as viewed from the front side thereof, withcertain components being shown in section;

FIG. 2 is a small-scale sectional elevational view of the stockdistributor or flow spreader, as viewed from the left hand end shown inFIG. 1, the flow box per se and other parts of the machine having beenomitted in the interests of clarity;

FIG. 3A is an enlarged, greatly exaggerated sectional view at the line3A3A of FIG. 2 showing one extreme degree of relationship of certainwalls of the structure; FIG. 3B is a view similar to FIG. 3A showing anopposite extreme degree of relationship of certain walls of thestructure;

FIG. 4 is a fragmentary elevational view of one of the agitating rollsof the invention;

FIG. 5 is a sectional view on the line 55 of FIG. 4;

FIG. 6 is a broken side elevational view of a modified form of a stockdistributor or flow spreader and inlet box, as viewed from the frontside thereof, with certain components being shown in section; and

FIG. 7 is a broken top plan view, in smaller scale, of the modified formof the stock distributor or flow spreader shown in FIG. 6, with certainparts being shown in section.

In the following description and in the appended claims, variouscomponents and details thereof will be identified by specific names forpurposes of convenience. Such phraseology and terminology is for thepurpose of description and not of limitation, the expressions. beingemployed in a generic and descriptive sense only.

With continued reference now to the drawings, which illustrate typicaland preferred embodiments of the invention for purposes of disclosure, Ihave shown, in FIG. 1, the outflow end of a delivery section comprisinga first or inflow conduit, generally indicated by reference numeral 10,directing a flow of stock to a second conduit or flow spreader,sometimes identified as a stock distributor or approach chamber,generally indicated by reference numeral 12, same accommodating thestock in its flow toward and into a head box or flow box, generallyindicated by reference numeral 14, mounted adjacent the path of movementof the Fourdrinier wire in known manner.

The exact form of stock distributor and head box employed will bevariable to meet individual mill requirements, some mills having abasement or lower level to allow the disposition of certain equipmentbelow the general horizontal plane of the papermaking machine, andothers requiring all appurtenant equipment to be disposed above themachine room floor.

The fiow to head box 14, by means of a conventional pumping mechanism,not shown, is from a supply point, also not shown, through first orinflow conduit 10 comprising a feeder pipe 18 of circular cross sectionhaving an exit terminal or outflow suitably joined to a pipe connection2d of flow distributor 12 as by means of coupled complementary flanges22 and 24-, as shown. Said pipe connection 25}, also of circular crosssection, leads directly to the inlet or inflow of flow spreader 12.

Conveniently, the opening of the inlet or inflow end is circular thoughit may be square or rectangular or otherwise to accommodate itself tothe particular configuration which the inflow conduit may partake of.

The orifice at the slice being essentially in the form of a rectangle,it is my desideratum to convert the flow from the round cross section offeeder pipe 18 to a rectangular cross section by the fiow spreadingsystem now to be described.

As shown in FIGS. l3B, flow spreader 12 essentially is of a fan orfish-tail configuration having a main axis extending in a generallyvertical plane and will be seen to comprise vertically-extending rearand front walls 3t) and 32 respectively, which walls generally convergetoward each other from their lower to their upper extremities, and apair of oppositely-spaced outwardly-inclined ide walls 34, each havingopposite rounded side edges merging smoothly with the respectiveadjacent side edges of said rear and front walls, the well roundedconstruction permitting the most effective removal of the low energyfluid from the boundary layer of the stock stream, the surfacecurvatures desirably following the stream lines of the llow in theseregions, so as to lend value in the attainment of steady-state flow atand forward of the flow spreader outflow or outlet.

Said lowermost edges of walls 30 and 32, and the lowermost edges of theside walls 34, 34 merging therewith, define a point of fiber suspensionentry or inflow or throat into the fiow spreader proper and the pipeconnection is suitably connected thereto in any known and conventionalmanner.

The upper extremities of said walls 30, 32, 34 and 34 define the mouthor outflow or point of stock discharge from the flow spreader.

Each of the walls 30 and 32 converges inwardly from its opposite sideedges towards its own vertical center line, with the degree ofconvergence increasing gradually from the lowermost edge of the wall tothe uppermost edge thereof so as to allow a gradual pinching eifectthereat.

As will be observed by a comparison of FIGS. 3A and 3B, the degree ofconvergence along the uppermost edges of said walls may be within arange of a minimum of 2, as shown in FIG. 3A and a maximum of 30, asshown in FIG. 3B.

As previously mentioned, the major axes of the rear and front walls 30and 32 are additionally so related that each generally converges towardthe other at its uppermost extremity so as to provide therewithin achamber which gradually narrows in depth (as contrasted with width) fromits lowermost area towards its uppermost area so as to allow a graduallyincreasing resistance to flow in the passageway formed therebetween.

Such convergence of the general axes of the walls 30 and 32, coupledwith the inward depression or pinching of each wall toward its owncenter line, achieves an effect which forces the suspension to spreadout toward the sides of the conduit rather than to tend to concentratecentrally thereof, as would be the case were the resistance to flow notso slightly increased at the midseetion of the chamber and/or themidsection of the stream flow.

By such flow spreader structure, the stock is constrained to flowvertically upwardly through a defined fan-shaped flow chamber, thechamber having an ever-widening sideto-side dimension or width, and anever-thinning frontto-back dimension or thickness, with the thickness,at the upper extremity or exit or mouth, centrally of the width, beingless than the thickness at the upper extremity at the side edges.

By such design, the flow spreader demonstrates a capacity for graduallyand progressively converting a flow of circular cross section upon entrythereinto into a constantly widening and thinning stream which hasassumed a flow of generally rectangular cross section upon dischargetherefrom, it being understood that the widthwise dimension of the flowstream at the upper extremity or mouth will correspond substantially tothe lateral width of the associated head box component subsequently tobe described and width of the papermaking machine toward which the fiowis directed.

The separation and resultant eddying and vortex formation which occursalong the inner faces of the diverging walls 34, 34 are eliminated bythe addition to the fluid of the boundary layer by means of the pinchingof the walls 30 and 32 forcing quantities of the fluid from the centerof the stream toward those points where separation would normally occur.The added energy is thus discharged into the boundary layer in the formof added fluid from the main flow stream and imparts added momentums tothe fluid of the boundary layer, making it possible for the boundarylayer to overcome the adverse pressure gradient which it encounters inits flow path for some distance beyond the point where the energy isadded. In essence the quantities of fluid, defined as added energy,while they may be added at points along the diverging walls, the pointsare so large in number and so close together as to form a continuousline along the inner face of each diverging wall 34, 34.

Stated otherwise, the fiber suspension passes through the deliverysection 10 from the source of stock supply and is transformed from itsflow of circular cross section to a flow of ever-widening relativelyfiat cross section within the flow spreader, all so as to contribute tothe general purpose of precluding the development of uneven stockconditions at the web-forming area.

Of course, it will be understood that the flow spreader may be operatedin a horizontal or angular disposition as well as in the illustratedvertical position. One so horizontally disposed is hereinafter describedand shown in connection with FIGS. 6 and '7.

As known, a head box functions to deliver stock to the slice at theproper velocity, thoroughly and uniformly mixed, and free from crosscurrents, turbulence and eddies.

A large quiet head box will eliminate currents but such allows thefibers expression of their tendency to coagulate. A smooth flow atrelatively slow speed, with the fibers at rest relative to one another,is known to allow conditions that promote flocculation, slime formation,and stock accumulation in the dead spots.

Contrariwise, a strong agitation, while mixing the fibers thoroughly anddispersing them will create the very objectionable cross currents andeddies I seek to avoid.

The head box design hereof, accordingly, is a compromise between the twoextremes and comprehends interference devices to promote the requiredagitation so as to disperse the fibers.

The head box, now to be described, fulfills admirably the desiderata of:

(l) Allowing no surging at its entrance (2) Allowing no dead areastherewithin (3) Allowing no corners or sharp angles (4) Allowing auniform delivery to the slice (5) Maintaining a uniform, homogeneousfiber disper- (6) Eliminating entrained air (7) Precluding fiberflocculation The flow box or head box per se comprehendstransversely-spaced vertically-extending side walls 40 and 40 andinterconnected transversely-spaced vertically-extending forward andrearward end walls 42 and 44 respectively and a bottom wall 46 to definea pond therewithin.

As is conventional, a slice, generally indicated by 48, is provided, thestock and water flowing from the head box through the slice, said slicehaving the primary function to deliver a sheet of liquid of uniformthickness and equal velocity across the width of the web-forminginstrumentalities.

As known, a paper machine slice is essentially an orifice and may be ofany of several basic types.

Purely for illustrative purposes, same not forming a part of theinvention, I have here shown a Voith type of slice, it being one of theearliest type slices incorporated into higher speed machines and of adesign to allow a raising or lowering of a top lip 50 in relation to abottom lip 52, for maintaining a constant head above the wire 54 andstill increasing the quantity of flow through the slice.

Explanitorily, the operation of a paper machine for a grade or type ofpaper must be such as to deliver a constant amount of fibers at alltimes. The amount of water accompanying the fiber onto the web-formingelements may be varied to improve the formation or change the qualitiesof the finished sheet. In other words, the consistency (pounds offiber/pounds of water) in the head box can be varied and the adjustmentof the top lip of the slice will allow a constant head to be maintained.For example, if the machine tender wishes to reduce the head boxconsistency by adding more water, he can raise the top slice lip,increase the opening, and still maintain the head.

Small hand wheels 56 suitably supported on the wall 42 are spaced acrossthe width of the top slice lip 50 and related spindles 57 provide ameans for leveling the slice and providing uniform flow from one edge ofthe wide width to the other.

In known manner, a breast roll 58 is disposed adjacent the forward endof wall 46 and the endless wire 54 is entrained therearound as well asother components not shown.

A baffle, which may be formed from a generally vertically andupwardly-extending wall 60, may be, if desired, doubled upon itself toprovide a secondary wall 62, and is spaced inwardly of flow box rearwall 44 to provide an upwardly extending first pass or passageway 64defined by said walls 44 and 60 and the head box side walls 40 and 4h.

The lower extremities of walls 44 and 60 will converge slightly so as tomerge smoothly with and be jointed to the upper extremities ofrespective fiow spreader walls 30 and 32 and the lower extremities ofrespective flow spreader walls 34 and 34 in the accomplishment of theprovision of a head box entry which allows no surging thereat.

The said first pass 64 will thus be observed to comprise a slowlyenlarging passageway for the upward flow of the stock, which upward flowwill allow the elimination of air from the stock and will efiectuate ageneral slowing of the stock flow.

A downwardly-extending plate or vertical slice 66 is adjustablyassociated with headbox side walls 40, 40 and is vertically aligned withwall 60 to provide a variable opening 68 therebetween.

The adjustment means for said plate 66 is not shown and may partake ofany suitable and conventional design. It will be appreciated that wall60 functions as a dam over which the stock flows, which dam assists inmaintaining an even flow of fiber suspension at a reduced velocitywherefor uneven currents are precluded.

Said wall 6i? constitutes but one of the interference devices within thehead box to promote the required agitation for preventing flocformation.

A downwardly extending baflie wall 70 is spaced from and forwardly ofwall as in substantial parallelism therewith to provide passageway 72therebetween allowing the downward flow of the stock therethrough.

By such baffle means and the related bafiie 64?, it Will be appreciatedthat the flow of the stock and water is confined between the battles andis thus controlled so that the erratic circulation found in large boxesis virtually eliminated.

Wall 7%) provides a restricted opening '71 defined by the space abovelower wall 46, and by such restriction, the flow is slowed down to aconsiderably reduced rate of forward flow when it moves therethrough.

Forwardly of Wall 70, bottom wall 46 is inclined upwardly to provideanother passageway 74 of gradually increasing transverse depth ascontrasted with the lateral widthwise dimension, which dimension remainsstationary.

It will be thus appreciated that walls 60 and 70 consttiute one set ofinterference devices within the head box for promoting the requiredagitation to prevent floc formation.

During the flow through third pass 74, the suspension is subjected toagitation and mixing by a plurality of agitating units, each generallyindicated by numeral 80.

The agitators generally comprehend an arrangement and operation of aplurality of agitating units disposed in manner to keep the pond alive,to eliminate flocking, to destroy objectionable currents, and to betterprepare the stock for delivery through the slice to the forming wire ormold under controlled conditions of uniform velocity flow.

Basically, by such agitating units, I provide means whereby the stockstream meets identical resistance across its entire width and is evenlyfed to the forming surface at a single, selected velocity.Simultaneously therewith, I cure other specific prior art defectsinclusive of the formation of light and heavy streaks running in themachine direction at regular or varying spaced intervals across themachine width by the deliberate and intentional creation of a pattern ofa multiplicity of minute cross currents for effecting improved randomdispersion of the fibers.

As known, a momentary speed increase followed by a sudden speed decreasecreates small eddy currents which break up fiber fiocs. Pin racks,perforated plates and rolls have all been heretofore used for thispurpose.

The agitating units hereof effectuate a reduction in area through whichthe fluid flows.

At the point of reduced area, the stock velocity is increased and uponmoving past the agitating unit, the velocity of stock and water is againdecreased.

Each said agitating unit may comprise a longitudinally-extendingrotatable cylindrical shell or tube 82 with outwardly-projecting solidtrunnions 84 at opposite ends of said shell for insertion through therespective adjacent side wall of the head box in suitable journal orbearing means mounted in said side walls whereby the agitating unit maybe positioned between and intercoupled with the confining opposite headbox side walls in close running relationship therewith.

Understandably, as an alternative construction, shell 82 may be sleevedupon a longitudinally-extending rotatable control or roll shaft andsupported radially outwardly thereof in concentric manner as by aplurality of spiders, said control or roll shaft being journalled at itsopposite ends in the adjacent head box side walls.

On the outer peripheral surface of shell 82, a multiplic ity ofradially-arranged outwardly-extending fins or vanes 86 are stationarilysecured, each fin or vane being disposed angularly or obliquely relativeto the longitudinal axis of the shell.

The fins are grouped as groupments or sets, the fins of each groupmentor set being arranged in a longitudinallyextending row in equi-spaceddistance from each other Eli and parallel relationship as to of the rowbeing parallel to the longitudinal axis of shell.

The fins of a groupment or set divide the surface area of the shellalong the axis thereof as defined by said groupment or set into aplurality of substantially equal segmental sections. By virtue of theoblique disposition of the adjacent fins, the planes of the fins of onerow intersect the planes of the fins of a next adjacent row. The angleof fin disposition should not exceed 30 and, for best results, should bewithin the range of l25 relative to the longitudinal axis of the shell.

The fins of one set in one row and the fins of another set in theadjacent row are disposed in angularly intersecting planes as the shellis rotated.

The rows, there being 4 in number in the illustrated embodiment, areequidistant from each other, they being disposed approximately 90 fromeach other, though it will be understood that the number of rows can bevaried so that the angle therebetween may be greater than or less thansaid 90 As to their angular or oblique disposition, the fins of adjacentrows are alternately disposed to effectuate the reversing of crosscurrents which serve to mix the stock and to reorient the fibers so thatmany of them will have their longitudinal axes at right, orapproximately right, angles to the direction of flow instead of beingaligned with the flow, as is normal, thereby serving to tend to equalizedirectional strength and to aid in the formation of the web.

Further as to their angular or oblique disposition, the fins of oneaxial row may be arranged at a certain angle relative to the shelllongitudinal axis, and the fins of the next adjacent axial rows arepreferentially, though not obligatorily, arranged at an angle opposed tothe said certain angle in the said one axial row for purposes ofeflectuating, upon the shell rotation, opposing sets of miniature orlocalized cross currents in the sense that the set of miniature orlocalized cross currents enduced by the said one axial row are opposedby the set of miniature or localized cross currents enduced by the saidadjacent axial row to allow a wobbling or back-and-forth movement, onwhich is repeated over and over as the shell is rotated. Thereby ashearing action results which causes the stock to be deflected first inone direction and then in the opposite direction so as to allow completeoverlapping and intermingling before delivery to the forming pond,simultaneously avoiding stock flocculation and minimizing thedevelopment of erratic eddy currents and other non-uniform flowconditions.

Stated otherwise, the adjacent rows function to establish a wobbling orconstantly changing movement in the flow of the stock stream flowingtherepast, to the end that the assemblage functions as an improved meansfor insuring more random distribution of the fibers.

The agitating units will extends transversely of the path of stock flowthrough the box and in spaced relation to its discharge outlet adjacentthe forming medium so as to perform a passive direction or redirectionof the flow.

A rotative movement is imparted to each agitating unit by a power means,not shown. Preferably, the rolls are rotated in the same direction andin timed relation to the rate of flow though they may be rotated inopposite directions, if desired, and/ or at varying rates of speed sothat they are rotated either in unison or out of unison and at constantor at variable speeds.

As the shell is rotated within a single cycle of 360 of rotation, thefins present segments of mutating planes relative to the axis of theshell so as to create the said wobble action by impelling the stockfirst in one direction and then in another whereby the flow istransversely broken into a plurality of very fine cross currents. Thefins rotate to impart a wobble effect to the streams, as they flowbetween the fins and then flow into and merge with adjacent eddies toeffect the ultimate desired intereach other, with the axis the 12weaving and uniform fiber distribution in the sheet formation. By suchrotative movement, the shive problem wherein the fibers tend to depositand to string on the fins and the shell is solved.

It is contemplated that both the pitch and the dimensions of the finsmay be varied to satisfy specific requirements of use, and further thatthe shell and fin assemblage may be used as a single unit, or that aplurality of such assemblages may be cooperatively employed in a stackedor tandem or in an arcuately-arranged relationship.

As the fins are rotated within a 360 cycle, they circumscribe a wobblingeffect as they each rotate about a point defining the center of theshell. Being so mounted, they produce a fine pattern of rapidlyrecurring and reversing currents. That is, they present segments ofmutating planes so as to impart an oscillatory motion to the streams ofstock passing therebetween and thereby effectuate the randomdistribution of the fibers uniformly and evenly at all points throughoutthe length of the roll as the converging streams intermingle upon havingpassed between the fins on the roll.

As shown, a single lowermost agitating unit is disposed in the narrow,lower area of pass 74 and serves to insure good agitation, to overcomestagnation, and to offset the tendency of the stock to hug the bottomwall, it being especially well suited for certain grades of paper suchas the heavy, slow running grades.

Spaced upwardly thereabove, a pair of agitating units 30 are disposed inalignment as to each other in a plane angularly related to thehorizontal axis of the stock in the pond thereabove.

As shown, one agitating unit may be disposed slightly behind the otherso that the flow will meet resistance in the shorter path and avoid atendency to short circuit the wide path to the slice pond.

After entering the head box at the throat of minimum cross sectionalarea, the suspension flows upwardly into the first pass 64 of the headbox and flows transversely outwardly from said first pass throughopening 68 into second pass 72 and thence downwardly and beneath wall 71into third pass 74.

From third pass 74, the stock flows into the pond. The flow thereinbeing upward at a relatively slow rate, the elimination of other airentrapped in the stock is permitted.

From the pond, the stock flows directly through the sliceaforedescribed.

I show a modified embodiment form in construction in FIGS. 6 and 7 forpurposes of further disclosure, same comprehending a delivery sectioncomprising a conduit or feeder 118 of round cross sectional areadirecting a flow of stock to a second conduit or flow spreader or stockdistributor, generally indicated by reference numeral 112, of relativelyflat cross sectional area, same accommodating the fiow of stock into ahead box of flow box, generally indicated by reference numeral 114,mounted adjacent the path of movement of the Fourdrinier wire in knownmanner.

The flow to head box 114 by conventional pumping means (not shown) isfrom a supply point (also not shown) through feeder pipe 118 of circularcross section to the inlet of flow spreader 112.

The orifice at the slice being in the form of a rectangle, it is adesideratum to convert the flow from the round cross section of thefeeder pipe to rectangular cross section.

Flow spreader 112 is of the fan or fish-tail type having a main axisextending in this modification in a generally horizontal plane and willbe seen to comprise horizontally-extending upper and lower walls and 132respectively, which walls generally converge toward each other fromtheir entry to their discharge extremities, and a pair ofoppositely-spaced outwardly diverging side walls 134 each havingopposite rounded side edges merging smoothly with the respectiveadjacent side edges of said 13 upper and lower walls, thereby to form anenclosed fanshaped flow chamber.

Said walls 130 and 132 are each of greater width at their discharge endsthan at their entry ends so as to provide the aforesaid fan shapedeffect, flaring outwardly equidistantly from opposite sides of thecenter line of the entry edges of said walls 130 and 132, which entryedges define the point of fiber suspension or stock entry into thefiowspreader. The discharge edges of said walls define the point offiber suspension or stock discharge therefrom.

Additionally, said walls 130 and 132 are converged towards each other,more or less at their midsections, so as to further define therewithin achamber which narrows in depth (as contrasted with width) from its entryextremity towards its discharge extremity, wherefore the throat at thedischarge end presents more resistance to the flow and forces thesuspension to spread out toward the sides of the chamber rather thanconcentrate in the center thereof, were resistance to flow not soslightly increased at said center.

By such modified flow spreader structure, the stock is constrained toflow horizontally-forwardly through the fan-shaped flow chamber definingan ever-widening sideto-side dimension or width in combination with aneverthinning top-to-bottom dimension or thickness, with the thickness atthe exit extremity or mouth centrally of the width being less than thethickness at the exit extremity at the side edges.

The width of the exit extremity will correspond to the lateral width ofthe associated head box and the machine width.

Here again, it will be observed that the flow spreader has widened therectangular section progressively and gradually to the full width of themachine with a corresponding reduction in depth wherefor the stock flowstherein in a constantly widening and thinner stream and flows outwardlytherefrom to the related components.

The spreading length is according to the width of the flow inlet and thewidth of the flow box and the spreading angle is within limits that willpermit uniform spreading of the flow.

Stated otherwise, the fiber suspension is transformed from its flow ofcircular cross section to a flow of relatively fiat cross section withinthe flow spreader and is spread evenly Widthwise of the machine so as topreclude the development of uneven stock conditions at the web formingarea.

The flow box or head box per se comprehends transversely-spacedvertically-extending side walls 140 and interconnectedtransversely-spaced vertically-extending forward and rearward end walls142 and 144 respectively and a bottom wall 146 to define a pondtherewithin.

A breast roll 158 is disposed adjacent the forward end of bottom wall146 and an endless wire 154 is supported by said breast roll in knownmanner.

A slice 148 is provided above breast roll 158 and may be of conventionaldesign.

Wall 144 will be provided adjacent its lower end with an arcuateoutwardly-curved portion 145 extending transversely of its width toprovide an enlarged throat Within the head box and will have asubstantially horizontallyextending portion 147 at its lowermostextremity, which with a lowermost extremity 149 of bottom wall 146 willserve to provide a mouth of generally rectangular cross section whichmay be suitably connected to the exit extremities of the respective flowspreader walls 130 and 132.

Similarly walls 140 will be provided with appropriately configuredextensions 141 to be connected to the respective side walls 134 of theflow spreader.

Side walls 140, 140, rear wall 146, and forward wall 144 define apassageway 174 within the head box, said passageway forming anever-widening approach to the pond, same being accomplished by theupward inclina- 14 tion of wall 146 so that passageway 174 is ofgradually increasing transverse dimension.

- During the flow of stock to and through the pass 174, the suspensionis subjected to agitation and mixing by a plurality of agitating unitsor rectifying rolls and 180 which further aid in the means for improvingfiber formation in paper as the stock is directed toward the movingforming surface for deposit thereupon.

Each said agitating unit being similar in design and function to thatpreviously described, it does not appear necessary to define it further.

In this embodiment, one such agitating unit 180' is disposed in thesump-like portion provided at the base of wall in order that the stockentering the head box from the flow spreader 134 may be subjected todirect agitation before it enters the passageway 174.

Three such agitating units are disposed in the passageway 174 and aredisclosed as disposed in a plane angularly related to the horizontalaxis of the stock in the pond thereabove, three being illustrated toemphasize that the invention need not be limited to two such agitatingunits disposed in a plane angularly related to the horizontal axis ofthe stock, as in the embodiment of FIG. 1.

By employing one such agitating unit 180 at the inlet to the head box114, and by employing a multiplicity of such units 180 in the head boxproper, the agitating action is spread over the entirety of the areawithin the pass 174 and the pattern of fine currents created by theagitat ing rolls 180 and 130' is spread out and said currents overlapeach other to a degree so as to allow improved uniformity.

All prior art head box designs have one feature in common; therectifying rolls thereof, whether stacked longitudinally with respect tothe flow or otherwise do not effectively destroy the longitudinal flowpatterns.

Herein, I provide an agitating unit at the head box inlet and I stackagitating units within the head box transversely of the flow so as toeffectuate a breaking in the pattern at every one-quarter turn of eachsaid unit.

The rate of turning contemplated is within a ratio of 2:1 and 10:1,relative to the rate of flow past the agitators, all so as to effectuatea continuous and repetitive pattern of small cross currents.

It is believed that the gist of the invention will be clearly understoodfrom the foregoing disclosure and accordingly, further analysis thereofat this point is considered unnecessary, as I have in accordance withthe provisions of the patent statutes, described the construction andprinciple of operation of my invention together with the apparatus whichI believe to represent one of the best embodiments thereof, to the endthat others can, by applying current knowledge, readily adapt it forvarious applications without omitting features which, from thestandpoint of prior art, fairly constitute essential char acteristics ofits generic and/or specific aspects.

The claims are desired to include within the scope thereof all of saidsuitable variations, modifications and equival nts by whichsubstantially the results of the invention may be obtained through theuse of substantially the same or equivalent devices or means.Accordingly, limitation hereof should only be made as determined by aproper interpretation of the prior art and the scope of the subjoinedclaims, in which it is my intention to claim all novelty inherent hereinas broadly as possible.

Having thus described my invention in an exemplary embodiment, what Itherefore particularly point out and distinctly claim as new and desiredto secure by Letters Patent is:

1. In fiow control apparatus of the class described, alaterally-diverging conduit for containing a flowing stream of fluid,said laterally-diverging conduit increasing in width from its inflow toits outflow and decreasing in depth from its inflow to its outflow anddecreasing in depth along its centerline at a greater rate than inportions at either side of its centerline to form a pinched area alongthe centerline for diverting portions of the flowing stream toward thelaterally-diverging areas and facilitating removal of the lower energyfluid from adjacent the walls defining the laterally-diverging areas ineflectuating maintenance of the fluid thereat in a substantiallysteady-state flow condition and providing the fluid with a more uniformvelocity distribution across the width of the widened stream at theoutflow.

2. In flow control apparatus for eflectuating maintenance of a flowingstream of fluid in a substantially cad -state flow condition andproviding the fluid with a more uniform velocity distribution across thewidth of the stream upon discharge therefrom comprising alaterally-diverging conduit for containing the fluid stream, saidlateraliy-diverging conduit having an increasing width and a decreasingdepth between inlet and outlet and a depth longitudinally of itscenterline decreasing to a greater degree than in portions on oppositesides of the centerline for forming a pinched space longitudinally ofthe center line and diverting portions of the flowing stream toward thelaterally-diverging areas and facilitating removal of the lower energyfluid from adjacent the portions of the walls defining thelaterally-diverging areas.

3. in flow control apparatus of the class described, alaterally-diverging conduit for containing a flowing stream of fluid andtransforming an inflow of circular cross-section to an outflow ofgenerally rectangular cross-section and having diverging side walls andconverging opposite walls for directing a controlled amount of fluidfrom the longitudinal midsection toward the diverging side walls foreffecting increases in the average kinetic energy of portions of thefluid flowing within and adjacent the diverging side walls said conduitbeing further characterized by an increase in width from inflow tooutflow and a decrease in depth from inflow to outflow and a decrease indepth along the centerline at a greater degree than in portions on theopposite sides thereof.

4. In a papermaking machine, the improvement in a stock distributingmeans for converting a flowing stream of an aqueous suspension ofpaperrnaking fibers from a circular cross-section into a flattenedcross-section preliminary to discharge into a head box comprising, aninflow of circular cross-section connected to a source of stock supply,an outflow of generally rectangular crosssection connected to a headbox, a wall defining a main body interconnecting said inflow and outflowand gradually increasing in lateral width in fan-like manner from saidinflow to said outflow and gradually decreasing in depth from saidinflow to said outflow and gradually decreasing in depth along thecenterline thereof in greater degree than in portions on opposite sidesof the centerline.

5. In a papermaking machine, a stock distributing means for converting aflowing stream of an aqueous suspension of papermaking fibers from acircular cross-section into a flattened cross-section preliminary todischarge into a head box and including, a conduit having an inlet ofcircular cross-section connected to a source of stock supply and anoutlet of generally rectangular cross-section discharging into the headbox, said conduit gradually increasing in width and decreasing in depthin fan-like manner from the inlet to the outlet, the width of the outletbeing substantially the width of the head box, said conduit decreasingin depth along the longitudinal centerline thereof to a greater degreethan in areas on opposite sides of the centerline whereby the stock istransformed from a confined stream of circular cross-section into ashallow relatively-wide stream of generally rectangular crosssection.

6. in a papermalting machine, in combination, a stock distributingmember for converting a flowing stream of an aqueous suspension ofpaperrnaking fibers from a circular cross section into a flattened crosssection, a head box connected to and taking delivery of the flow streamfrom said stock distributing member, said stock distributto ing membercomprising a fan-shaped conduit having an inlet end of circular crosssection connected to a source of supply and an outlet end of generallyrectangular cross section discharging into said head box substantiallythe entire width thereof and increasing in Width and decreasing in depthfrom the inlet end to the outlet end and decreasing in depth along itscenterline at a greater rate than in portions on either side of thecenterline wherewith the flow stream discharges evenly and at a uniformvelocity across the entire outlet end and into said head box.

7. In a papermaking machine as set forth in claim 6 wherein said stockdistributing means includes verticallyextending front and rear wallsgenerally converging toward each other from their lower to their upperextremities, and a pair of oppositely-spaced outwardly-inclined sidewalls having rounded side edges merging with the adjacent side edges ofsaid front and rear walls, thereby to form an enclosed fan-shapedchamber.

8. In a papermaking machine, a stock distributing means for converting aflowing stream of an aqueous suspension of paperrnaking fibers from acircular cross section into a flattened cross section preliminary todischarge into a head box comprising, delivery conduit means having aninlet end of circular cross section connected to a source of stocksupply and having an outlet end of generally rectangular cross sectiondischarging into the head box, said conduit increasing in lateral widthand decreasing in transverse depth from said inlet end to said outletend, the lateral width of said outlet end being substantially the widthof the head box, said conduit decreasing in depth along its centerlineto a greater degree than in portions on opposite sides of thecenterline.

9. In a papermaking machine, a stock distributing conduit for convertinga flowing stream of an aqueous suspension of paperrnaking fibers from acircular cross section at its inflow into a flattened generallyrectangular cross-section at its outflow preliminary to discharge into ahead box comprising, delivery conduit means having an outflow ofcircular cross section connected to a source of stock supply andcommunicating with the conduit inflow, said conduit increasing in widthin fan-like manner from the conduit inflow to the conduit outflow withthe width of said outflow being substantially the width of the head boxand decreasing in depth from said inflow to said outflow and decreasingin depth along its centerline to a greater degree than in portions oneither side of the centerline.

10. In flow control apparatus of the class described, alaterally-diverging conduit of generally expanding crosssectional areafor containing a flowing stream of fluid, said laterally-divergingconduit having a greater crosssectional area at its outflow than at itsinflow by virtue of a width increasing from inflow to outflow and adepth decreasing from inflow to outflow and a depth decreasing along itscenterline to a greater degree than in portions on opposite sides of thecenterline for eflectuating diversion of increasing portions of thefluid stream toward the laterally-diverging areas in quantitiessufficient to effect removal of the lower energy fluid in themaintenance of the fluid in a substantially steady-state flow conditiontherewitln'n with a uniform velocity distribution across the width ofthe widened stream at the outflow.

References Cited in the file of this patent UNITED STATES PATENTS1,707,375 Upson Apr. 2, 1929 2,465,445 Goldsmith Mar. 29, 1949 2,788,719Bennett Apr. 16, 1957 2,865,260 Lee Dec. 23, 1958 FOREIGN PATENTS440,431 Great Britain Dec. 30, 1.935

874,698 Germany Apr. 27, 1953

1. IN FLOW CONTROL APPARATUS OF THE CLASS DESCRIBED, ALATERALLY-DIVERGING CONDUIT FOR CONTAINING A FLOWING STREAM OF FLUID,SAID LATERALLY-DIVERGING CONDUIT INCREASING IN WIDTH FROM ITS INFLOW TOITS OUTFLOW AND DECREASING IN DEPTH FROM ITS INFLOW TO ITS OUTFLOW ANDDECREASING IN DEPTH ALONG ITS CENTERLINE AT A GREATER RATE THAN INPORTIONS AT EITHER SIDE OF ITS CENTERLINE TO FORM A PINCHED AREA ALONGTHE CENTERLINE FOR DIVERTING PORTIONS OF THE FLOWING STREAM TOWARD THELATERALLY-DIVERGING AREAS AND FACILITATING REMOVAL OF THE LOWER ENERGYFLUID FROM ADJACENT THE WALLS DEFINING THE LATERALLY-DIVERGING AREAS INEFFECTUATING MAINTENANCE OF THE FLUID THEREAT IN A SUBSTANTIALLYSTEADY-STATE FLOW CONDITION AND PROVIDING THE FLUID WITH A MORE UNIFORMVELOCITY DISTRIBUTION ACROSS THE WIDTH OF THE WIDENED STREAM AT THEOUTFLOW.